1. Field of the Invention
The present invention relates to a keyboard musical instrument and a solenoid drive mechanism.
2. Description of the Related Art
As a key-depression drive mechanism of a keyboard musical instrument for automatic performance, for example, a solenoid is used (for example, Japanese Patent Publication No. 3799706). In many cases, in order to obtain a large force for retaining a key at a finish position (hereafter referred to as an end position) where the key is situated after a depression of the key, the solenoid is designed such that a force generated by the solenoid at the end position is larger than that generated at an initial position (hereafter referred to as a rest position) where the key is situated before the depression thereof (in other words, such that the solenoid is efficient). Hereafter a force generated by a solenoid is referred as a solenoid force. When the key is situated near the rest position and the solenoid force is small, however, the response in the early stage of the driving for key-depression is not fast, resulting in difficulty in performance expressions which require quick passages.
In addition, a solenoid is used for exerting a sense of force in response to a player's depression of a key, for example. In order to enrich performance expressions on a keyboard musical instrument, for example, it is desired to improve the control over a solenoid force.